Safety systems
Display messages Possible causes/consequences and
M Solutions
!÷
currently unavail‐
able See Owner's
Manual G
Risk of accident
ABS,E SP®
,B AS ,PRE-SAFE ®
,t he HOLD function, hill start assist
and ESP ®
trailer stabilisation are temporarily not available.
The adaptive brake lights, BAS PLUS and PRE-SAFE ®
Brake may
also have failed.
In addition, the ä,åand! warning lamps light up in
the instrumen tcluster.
For example, the on-board voltage may be insufficient.
ATTENTIONA SSIST is deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
X Drive on carefully.
If the display message disappears, the functions mentioned
above are available again.
If the display message continues to be displayed:
X Drive on carefully.
X Visit aqualified specialist workshop. !÷
inoperative See
Owner's Manual G
Risk of accident
ABS,E SP®
,B AS ,PRE-SAFE ®
,t he HOLD function, hill start assist
and ESP ®
trailer stabilisation are not available due to amalfunc-
tion.
The adaptive brake lights, BAS PLUS and PRE-SAFE ®
Brake may
also have failed.
In addition, the J,ä,åand! warning lamps light
up in the instrumen tcluster.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
ATTENTION ASSIST is deactivated.
X Drive on carefully.
X Visit aqualified specialist workshop immediately. Display messages
233On-board computer and displays Z
Display messages Possible causes/consequences and
M Solutions
÷
inoperative See
Owner'
sManual G
Risk of accident
ESP ®
,B AS ,PRE-SAFE ®
,t he HOLD function ,hill start assist and
ESP ®
trailer stabilisation are no tavailabled ue toamalfunction.
The adaptive brake lights, BAS PLUS and PRE-SAFE ®
Brake may
alsoh ave failed.
In addition, the äandå warning lamp slight up in the
instrument cluster.
ATTENTION ASSIST is deactivated.
The brake system continues to function normally, but without the
functions listed above.
X Drive on carefully.
X Visi taq ualified specialist workshop. T!
÷ G
Risk of accident
EBD( electronic brake forc edistribution), ABS, ESP ®
,B AS ,PRE-
SAFE ®
,t he HOLD function ,hill start assist and ESP ®
trailer stabi-
lisatio nare not available due to amalfunction.
The adaptive brake lights, BAS PLUS and PRE-SAFE ®
Brake may
alsoh ave failed.
In addition, the ä,åand! warning lamp slight up in
the instrument cluster and awarning tone sounds.
ATTENTION ASSIST is deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels coul dtherefore lock if you
brake hard ,for example.
X Drive on carefully.
X Visi taq ualified specialist workshop immediately. J
Releas
eparking brake You are drivin
gwith the parkin gbrake applied. Awarning tone also
sounds.
X Release th eparking brake. 234
Display messagesOn-boar
dcomputer and displays
Display messages Possible causes/consequences and
M Solutions
J
Brake immediately Am
alfunction has occurred while th eHOLDf unction or DIS-
TRONIC PLU Sisactive.
or
Vehicles wit hmanual transmission: wit hthe HOLD function acti-
vated, you hav eeither:
R opened th edriver's doo rand released the sea tbelt or
R switched off the engin eor
R opened the bonnet
At one may also sound at regular intervals. The toneb ecomes
louder if you attempt to lock the vehicle.
You cannot start the engine.
X Paying attention to the traffic situation, immediately depress the
brake pedal firmly and hold until the display message disap-
pears.
X Prevent the vehicle from rolling away before you leave it
(Y page 301).
You can restart the engine. J
Check brake fluid
level G
Risk of accident
There is insufficient brake fluid in the brake fluid reservoir. In addi-
tion, the red Jwarning lamp in the instrument cluster lights
up and awarning tone sounds.
X Pullo ver and stop the vehicl esafel yass oon as possible,p aying
attention to road and traffic conditions. Do not continue driving
under any circumstances.
X Apply the parking brake.
X Consult aqualified specialist workshop.
X Do not top up the brake fluid. This does not correct the error. #
Check brake wear The brake pads/linings have reache
dtheir wearl imit.
X Visit aqualified specialist workshop. PRE-SAFE
inoperative See
Owner's Man. G
Risk of injury
Important function sofPRE-SAFE ®
have failed .All other occupant
safet ysystems, e.g. airbags, remain available.
X Visit aqualified specialist workshop immediately. Display messages
235On-board computer and displays Z
Display messages Possible causes/consequences and
M Solutions
PRE-SAFE
Functions cur‐
rently limited See
Owner'
sManual G
Risk of accident
PRE-SAFE ®
Brake is temporarily inoperative if:
R theD ISTR ONIC PLU Scover in th eradiato rgrille is dirty.
R thes ensor sinthebumpers are dirty.
R itsf unction is impaire ddue to heav yrain or snow.
R ther ada rsensor system is temporarily inoperative, e.g. due to
electromagnetic radiation emitted by nearby TV or radio sta-
tion soro ther sources of electromagnetic radiation.
R the system is outside the operatin gtemperature range.
R the on-board voltage is too low.
PRE-SAFE ®
Brak eiso perational again and the display message
disappears if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detects that the sensor sare fully available again.
R the system is within the operatin gtemperature range.
If the display message continues to be displayed:
X Clean the DISTRONIC PLUS cover in the radiator grille
(Y page 290).
X Clean the bumpers (Y page 290).
X Restart the engine.
X Wait until the batter yissufficiently charged. PRE-SAFE
Functions limited
See Owner's Manual G
Risk of accident
PRE-SAFE ®
Brak eisf aulty. BASP LUS or the distance warning sig-
nal may also have failed.
X Visit aqualified specialist workshop. A
Malfunction Con‐
sult workshop G
Risk of injury
Cabriolet: the roll bars are defective.
X Visit aqualified specialist workshop immediately. ü If the symbola
ppears in the multifunction display,as eat belt
tongue has been clipped intoar ear seat belt buckle.
For further information on the status indicator for the rear seat
belts: (Y page 49). 236
Display messagesOn-boar
dcomputer and displays
Display messages Possible causes/consequences and
M Solutions
ý G
Risk of injury
If th esymbol appears in th emultifunction display, aseat belt
tongue has not been clipped intoar ear seat belt buckle.
X If necessary, ask the occupants in the rear to fasten their seat
belts.
For further information on the status indicator for the rear seat
belts: (Y page 49). Child seat in
wrong position
See Owner's Manual G
Risk of injury
Vehicles with automatic child seat recognition on the front-
passenger seat: the child seat is positioned incorrectly.
X Fit the child seat in the correct position. G
Risk of injury
Vehicles with automatic child seat recognition on the front-
passenger seat: the automatic child seat recognition sensor is
faulty.
X Visit aqualified specialist workshop. 6
Restraint
sys. mal‐
functio
nConsult workshop G
Risk of injury
There is amalfunction in the SRS (Supplemental Restraint Sys-
tem). The 6warning lamp also lights up in the instrument clus-
ter.
X Visit aqualified specialist workshop. 6
Front
left malfunc‐
tion Consult work‐
shop or
Front right malfunction
Consult workshop G
Risk of injury
SRS has malfunctioned at the fron tonthe left or right. The 6
warning lamp also lights up in the instrument cluster.
X Visit aqualified specialist workshop. Display messages
237On-boardcomputer and displays Z
Display messages Possible causes/consequences and
M Solutions
b
Intell
.Light Sys‐ tem inoperative The Intelligent Light Syste
misfaulty. The lights remain available
without the Intelligent Light System.
X Visit aqualified specialist workshop. b
Malfunction See
Owner's Manual The exterior lighting is faulty.
X
Visit aqualified specialist workshop. Vehicles with trailer tow hitch:
afuse may have blown.
X Check the fuses (Y page 313).
X If necessary, replace the blown fuse. Observe the warning notes
as you do so.
If the displaym essage continues to be displayed:
X Visit aqualified specialist workshop. b
AUTO
lights inoper‐
ative The light sensor is faulty.
X
Visit aqualified specialist workshop. b
Switch off lights The lights are still switched on when you leave the vehicle. A
warning tone also sounds.
X
Turn the light switch to Ã.Adaptive Main-beam
Assist inoperative Adaptive Highbeam Assist is faulty.
X
Visit aqualified specialist workshop. Adaptive Main-beam
Assist currently
unavailable See
Owner's Manual Adaptive Highbeam Assist is deactivated and temporarily inoper-
ative if:
R
the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
X Cleant he windscreen.
Adaptive Highbeam Assist is available again if:
R the dirt (e.g. slush) drops away while the vehicle is in motion.
R the system detectst hat the camera is fully operational again.
The Adaptive Main-beam Assist available again message
is displayed. Display messages
241On-board computer and displays Z
Engine
Display messages Possible causes/consequences and
M Solutions
+
Top
up coolant See
Owner'
sManual The coolant leve
listoolow.
X Top up th ecoolant ,observing th ewarning note sbefore doing
so (Y page 283).
X If th ecoolant needs toppin gupmoreo ften than usual, have the
engin ecoolant system checked at aqualifie dspecialist work-
shop. ?
Coolan
tStopv ehi‐ cle Switch engine
off The coolant is to
ohot.
Aw arning tone also sounds.
X Stop th evehicle immediately, payin gattentio ntoroad and traf-
fic conditions, and switch off the engine.
X Make sure that the air supply to the engine radiator is not
blocked, e.g. by frozen slush.
X Wait until the display message disappears before restarting the
engine. Otherwise, there is arisk of engine damage.
X Pay attention to the coolant temperature display.
X If the temperature increases again, visit aqualified specialist
workshop immediately. The poly-V-belt may have torn.
X
Stop the vehicle immediately, paying attention to road and traf-
fic conditions, and switch off the engine.
X Open the bonnet.
X Check whether the poly-V-belt is torn.
If the poly-V-belt is torn:
! Do not continue driving. The engine could otherwise overheat.
X Consult aqualified specialist workshop.
If the poly-V-belt is OK:
X Wait until the display message disappears before restarting the
engine. Otherwise, there is arisk of engine damage.
X Pay attention to the coolant temperature display.
X Visit aqualified specialist workshop. ? The fan motor is faulty.
X
If the coolant temperature is less than 120 †, you can continue
driving to the nearest qualified specialist workshop.
X Avoid heavy loads on the engine as you do so, e.g. driving on
mountain roads and stop/start driving. 242
Display messagesOn-board computer and displays
Display messages Possible causes/consequences and
M Solutions
Radar sensor
deactivated autom.
See Owner'
sManual Vehicles wit
hanavigation system: th evehicl eisc lose to aradio
telescope facilit yand is therefore prohibite dfromt ransmitting any
rada rsignals .The radar sensor system has switched off automat-
ically (Y page 345).
DISTRONIC PLUS (Y page 171) is deactivated automatically if it is
activated. Awarning tone also sounds.
Blin dSpotA ssist (Y page 196) or Active Blind Spot Assist
(Y page 199) is deactivated automaticallyifitisa ctivated. The
yellow 9indicator lamps also light up in the exterior mirrors.
BAS PLUS (Brake Assist PLUS) (Y page 62) and PRE-SAFE®
Brake
(Y page 66) are also not available.
X Drive on.
Once you have moved far enough awayf rom the radio telescope,
the above functionsa re available again.Radar sensor
deactivated See
Owner's Manual The radar sensor system is deactivated.
X
Check whether or not the radar sensor system may be activated
(Y page 345).
X Switch on the radar sensor system (Y page 229).Lane Keeping
Assist currently
unavailable See
Owner's Manual or
Active Lane Keep‐ ing Assist cur‐
rently unavailable
See Owner's Manual Lane Keeping Assist or Active Lane Keeping Assist is deactivated
and temporarily inoperative if:
R the windscreen is dirty in the camera's field of vision.
R visibility is impaired due to heavy rain, snow or fog.
R there are no lane markings for alonger period.
R the lane markings are worn, dark or covered, for example by dirt
or snow.
Lane Keeping Assist or Active Lane Keeping Assist is operational
againa nd the display message disappears if:
R the dirt (e.g. slush) drops away whil ethe vehicl eisinmotion.
R the system detects tha tthe camera is fully operational again.
If the displaym essage continues to be displayed:
X Cleant he windscreen. Lane Keeping
Assist inoperative
or
Active Lane Keeping Assist
inoperative Lane Keeping Assist or Active Lane Keeping Assist is faulty.
X
Visit aqualified specialist workshop. Display messages
245On-board computer and displays Z